(a) Field of the Invention
The invention relates to a robot arm for delivering a wafer, a wafer-operating machine and a member thereof, particularly to a robot arm for delivering a wafer, a wafer-operating machine and a member thereof which produce a less amount of ducts and decrease wear and tear on these devices.
(b) Description of the Related Art
In general, robot arms of a semiconductor manufacturing machine approximately include three types: vacuum, clamp and backside contact. Robot arms of the vacuum type and the clamp type are unable to change the direction of a wafer, and robot arms of the backside contact type tend to easily produce particles due to clamp operation. A wafer sorter is used to sort and deliver wafers in the process of manufacturing a semiconductor. Since the wafers may need to be changed their direction during the sorting and delivering operation, the robot arm of the backside contact type is used in the wafer sorter.
FIG. 1 shows a top view of a conventional robot arm for delivering a wafer. FIG. 2 shows a cross-sectional view taken along section line A-A′ in FIG. 1. As shown in FIG. 1, the robot arm 10 includes a driving device 11 and a carrier plate 12. The driving device 11 is connected to the carrier plate 12. When a wafer 13 is on the carrier plate 12, the driving device 11 moves the carrier plate 12 to transfer the wafer 13. In general, a plurality of contact pads 14 is disposed on an inner ring 15. In a conventional art, the contact pads 14 are pasted with adhesive glue on one surface of the inner ring 15 so as to prevent the wafer being in contact with the surface of the carrier plate 12. Since the contact pads 14 are frequently in contact with the bottom surface of the wafer 13, there is wear and tear on the contact pads 14. As a result, the contact pads 14 must be replaced on a regular time schedule, which increases the manufacturing cost. In addition, the wafer-operating machine must be adjusted after the replacement of the contact pads 14, so that the wafer 13 can be horizontally location on the contact pads 14 of the inner ring 15.
As above stated, there is a need for a preferred robot arm in the manufacture of semiconductor devices such that the amount of the dusts produced is less, the wear and tear on the contact pads 14 is improved, and the time needed for adjusting the machine is reduced.